Various abnormalities of the neurological system, such as brain and spinal tumors, cysts, lesions, or neural hematomas, can cause severe health risks to patients afflicted by them, including deterioration in motor skills, nausea or vomiting, memory or communication problems, behavioral changes, headaches, or seizures. In certain cases, resection of abnormal tissue masses is required. However, given the complexity and importance of the neurological system, such neurosurgical procedures are extremely delicate and must be executed with great precision and care.
There a several different types of procedures that may be used to resect brain and spine tissue. One such procedure is open transcranial surgery; another is endonasal neurosurgery, whereby the neurosurgical procedure is conducted through the nose. Each procedure has its own advantages, depending on where an abnormality is located. For abnormalities associated with the pituitary gland, for example, an endonasal approach is particularly useful. A prior art endonasal neurosurgical procedure will now be explained, with reference to FIGS. 1 and 2.
Referring to FIGS. 1-2, first the anatomy of the nose 10 will be explained. As illustrated in FIG. 1, the nose 10 includes a plurality of turbinates 12 positioned within a nasal cavity 14. Access to nasal cavity 14 may be accomplished through the nostrils 16. Positioned beyond nasal cavity 14 is the cranium 18, a boney covering that protects the brain 20. Positioned in a central part of the brain is the pituitary gland 22. Situated between pituitary gland 22 and nasal cavity 14 is the sphenoid sinus 24, a cavity lined with mucus. A back wall of sphenoid sinus 24 is makes up an anterior wall of the sella turcica 26. Sella turcica 26 is a boney structure at the base of the skull in which pituitary gland 22 is positioned. Surrounding brain 20 and pituitary gland 22 is the dura 28. Dura 28 is a thin membrane that acts as a bag to contain cerebrospinal fluid.
In a prior art neurosurgery (and in spinal surgery), the following steps were performed. First, a pathway was formed. This is accomplished by using a punch device to remove tissues or boney material. In a prior art endonasal surgery, a punch device was used to remove one or more of the turbinates. Know punch devices, such as a Kerrison punch, include a slidable blade member that simply moves against a wall member so as to pinch a portion of the tissue (such as turbinates) therebetween. The slidable blade and wall member effectively grips and then tears the turbinate from its substrate in the nasal cavity. However, due to the size constraints of the nasal passages, the punch device must be small enough to be received within the nasal passage and only a limited amount of tissue may be removed with each sliding movement of the blade. Thus, after each punch operation, the punch device must be removed from the nasal passageway to remove the torn tissue from the punch device. Accordingly, multiple insertions must be made of the punch device (and multiple tissue removal operations) to clear the nasal passageway of the turbinates, lengthening the procedure and causing increased trauma to the patient, as well as increase bleeding in the nasal passageway. Further, to clear the bleeding and any mucoid secretions, insertion of separate section device was necessary, even further lengthening the procedure.
Once the pathway was created, the next step in a prior art endonasal surgery procedure is to create access to the brain. As shown in FIG. 2A, there are multiple access directions that can be taken to accomplish access to the brain. More specifically, the following approaches may be taken, the transcribriform TA, the transpianum TB, the transsphenoidal TC, and the transclival TD. The various approaches are the results of different directions through the sphenoidal sinus. 24. For surgical procedures whereby tissue adjacent the pituitary gland 22 (where a significant number of abnormalities are found) is to be resected, a pathway through the sella turcica 26 must be created.
In prior art systems, the sella turcica 26 is simply ground to dust, effectively eliminating a complete section of the boney structure to provide access to the dura layer of the brain. A slit is then formed in a section of the dura layer, to provide access to brain tissue.
Once the brain tissue is exposed, a resecting device is inserted through the nostril and nasal cavity and used to excise tissue. However, many known tissue cutting devices suffer from an inability to quickly and cleanly sever neurological tissue samples without causing “traction” or pull on the surrounding tissue. Like the Kerrison punch device, known tissue cutting devices often tear tissue, causing undesirable trauma to the surround tissue. In addition, many known devices are not configured to both “debulk” large structures and to finely shave smaller, more delicate structures and lack the flexibility needed in many procedures. Furthermore, many neurological procedures impose significant space limitations on the surgeon, and the tissue resection device needs to be manipulable by the surgeon with one hand in relatively small spaces. In some cases, known devices also emulsify resected tissue, rendering it unsuitable for subsequent analysis (e.g., histologic analysis).
Once tissue samples are excised and the procedure is completed, a fat graft is harvested from abdomen or a graft of muscle and fascia is harvested from the lateral thigh, causing additional trauma to the patient. The graft is placed in the hole that was formed in the sella turcica 26, effectively plugging the hole created by the removal of the boney structure. While the grafts serve to prevent subsequent leakage of cerebrospinal fluid, the brain is still more susceptible to trauma, as the grafts are less robust than the patient's original dura and boney structure making up the sella turcica 26, and the fat grafts must be packed sufficiently tight to create a watertight seal to prevent leakage of cerebrospinal fluid.